The invention relates generally to polymers, and particularly to polymers comprising phenyl pyridine units, monomers for preparing the polymers and optical electronic devices using the polymers.
Optical electronic devices, e.g. Organic Light Emitting Devices (OLEDs), which make use of thin film materials that emit light when subjected to a voltage bias, are expected to become an increasingly popular form of flat panel display technology. This is because OLEDs have a wide variety of potential applications, including cellphones, personal digital assistants (PDAs), computer displays, informational displays in vehicles, television monitors, as well as light sources for general illumination. Due to their bright colors, wide viewing angle, compatibility with full motion video, broad temperature ranges, thin and conformable form factor, low power requirements and the potential for low cost manufacturing processes, OLEDs are seen as a future replacement technology for cathode ray tubes (CRTs) and liquid crystal displays (LCDs). Due to their high luminous efficiencies, OLEDs are seen as having the potential to replace incandescent, and perhaps even fluorescent, lamps for certain types of applications.
OLEDs possess a sandwiched structure, which consists of one or more organic layers between two opposite electrodes. For instance, multi-layered devices usually comprise at least three layers: a hole injection/transporting layer, an emissive layer and an electron transporting layer (ETL). Furthermore, it is also preferred that the hole injection/transporting layer serves as an electron blocking layer and the ETL as a hole blocking layer. Single-layered OLEDs comprise only one layer of materials between two opposite electrodes.
OLEDs are not very popular nowadays yet due to stabilities and/or feasibilities thereof. People are trying to improve OLEDs in many ways, one of which is to provide materials more suitable for OLEDs.